US7046154B2 - Flame-monitoring device - Google Patents
Flame-monitoring device Download PDFInfo
- Publication number
- US7046154B2 US7046154B2 US10/477,005 US47700503A US7046154B2 US 7046154 B2 US7046154 B2 US 7046154B2 US 47700503 A US47700503 A US 47700503A US 7046154 B2 US7046154 B2 US 7046154B2
- Authority
- US
- United States
- Prior art keywords
- voltage
- flame
- monitoring apparatus
- limiter
- asymmetry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime, expires
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
- F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/26—Details
Definitions
- the present invention concerns a flame monitoring apparatus.
- DE-OS No. 1 815 968 discloses a flame monitoring apparatus in which an ac voltage is supplied to a transformer and subsequently to a peak voltage limiter. The transmission of voltage peaks from the mains to the operating circuit is prevented by the peak voltage limiter.
- the voltage limiters used for that purpose are for example voltage-dependent resistors (VDR) which provide a limiting effect in a bipolar mode, that is to say in both voltage directions.
- VDR voltage-dependent resistors
- a problem of such flame monitoring apparatuses is rectifier effects at the burner, which are not flame-induced, for example in the case of ionization electrodes due to chemical actions between the monitoring electrode and the reference ground.
- One advantage of the present invention is to make flame monitoring apparatuses of the kind set forth in the opening part of this specification insensitive in relation to non-flame-induced rectifier effects, by suitable measures.
- one advantage of the invention is that an asymmetric limit voltage which acts on the sensor can be produced.
- Zener diodes are used to produce an asymmetric voltage, it is possible even to cope with device faults in respect of the Zener diode, due to the higher number of Zener diodes in one direction. If a Zener diode fails there are still sufficient diodes for reliable operation of the voltage limiter. The greater the number of additional Zener diodes that are provided to produce the asymmetry, the correspondingly greater faults it is then possible to compensate.
- Zener diodes does not exhibit any voltage dependency in comparison with varistors (with small series resistors) and temperature compensation can also be implemented by the use of Zener diodes with different temperature coefficients.
- Zener diodes permits ac voltage stabilization with standard components which can be obtained from a number of manufacturers.
- Implementation of ac voltage limitation by means of diodes also affords the advantage that, for example if it may be necessary that the limited ac voltage of an automatic firing device has to be switched over between two voltage values within a switching sequence, a voltage change-over switching operation can be easily implemented by bridging over some diodes of the diode array. In that case the desired voltage variation can be freely selected by way of the choice of the diodes.
- VDR voltage-dependent resistors
- FIG. 1 diagrammatically shows a flame monitoring apparatus
- FIG. 2A shows an equivalent circuit for an ideal flame
- FIG. 2B shows an equivalent circuit for a real flame
- FIG. 2C shows an equivalent circuit for a contaminated electrode
- FIG. 3 shows an asymmetric ac voltage limiter
- FIG. 4A shows the ac voltage at U 1 .
- FIG. 4B shows the asymmetric ac voltage at U 2 .
- FIG. 4C shows a symmetrical ac voltage U 2 * from the state of the art
- FIG. 5A shows the pattern of the current i with an ideal flame
- FIG. 5B shows the pattern of the current i with a contaminated electrode and asymmetric ac voltage
- FIG. 5C shows the pattern of the current i with a contaminated electrode and symmetrical ac voltage.
- FIG. 1 diagrammatically shows a flame monitoring apparatus which is fed with an input voltage U 1 for example by way of a mains ac voltage 1 and by way of a transformer 2 .
- the behavior of the input voltage U 1 is diagrammatically shown in FIG. 4A .
- the input voltage U 1 is limited to the limit voltage U 2 by way of a resistor 3 and a voltage limiter 4 , see FIG. 4B .
- a flame 6 can be produced by a burner 5 .
- An ionization electrode 7 projects into the flame region of the flame 6 .
- the ac voltage U 2 is applied to the burner 5 , and the ionization electrode 7 .
- a rectified ionization current occurs due to the flame 6 and the applied ac voltage U 2 .
- the ac voltage is filtered out by means of a low pass filter comprising a resistor 8 and a capacitor 9 and only the direct component which is used as a flame signal is passed to an amplifier 10 in which the flame signal is amplified and passed to a regulating device (not shown) for further processing.
- the ionization electrode it is also possible to use a UV-sensor or any sensor which acts on the rectification effect of the flame amplifier signal. Under certain conditions those sensors also have undesirable rectification effects, for example with mains voltages with a dc voltage offset or in the case of certain defects in the sensors.
- Such sensors as well as the ionization electrode shown in FIG. 2 can be described by the equivalent circuits of FIGS. 2A and 2B in order to clarify the behavior thereof.
- FIG. 2A shows the burner, illustrated in FIG. 1 between the points A and B, with the flame and the ionization electrode, in the form of an equivalent circuit for an ideal behavior with a diode 21 and a resistor 20 in series.
- the diode produces the same rectification effect as the flame.
- FIG. 2B shows the burner, illustrated in FIG. 1 between the points A and B, with the flame and the ionization electrode, in the form of an equivalent circuit for the real behavior with a diode 21 and a resistor 20 in series, with which a resistor 22 is connected in parallel.
- current flows not only in the forward direction of the diode 21 but also in the reverse direction of the diode.
- FIG. 2C shows the burner, illustrated in FIG. 1 between the points A and B, with the flame and the ionization electrode, in the form of an equivalent circuit for the real behavior in the case of a contaminated electrode with a diode 21 and a resistor 20 in series, with which a resistor 22 is connected in parallel and a diode 23 and a resistor 24 in series is connected in parallel.
- FIG. 3 shows a voltage limiter according to the invention for producing an asymmetric voltage, comprising diodes 31 which conduct even in the reverse direction from a certain voltage on, for example so-called Zener diodes, in which respect additional Zener diodes 32 are so arranged in one direction that the voltage in the forward direction of the diode 21 is increased in relation to the voltage in the reverse direction.
- Zener diodes are so arranged in one direction that the voltage in the forward direction of the diode 21 is increased in relation to the voltage in the reverse direction.
- the direction of installation of the voltage limiter is indicated from the points C and D which correspond to the points C and D in FIG. 1 .
- the number of Zener diodes used is dependent on the respective situation of use and has to be specifically designed for each case. It is advantageous however for the asymmetry to be effected over two diodes in order not to involve a flame simulation even in the event of a possible duplicate defect.
- the asymmetry can be limited to only 43V by the choice of 32 Zener diodes.
- the illustrated series resistors 33 are optional and serve for surge current limitation in the case of transient overvoltages.
- the diode section should preferably be made up only by way of diodes of the same type and of the same value, that is to say the same breakdown voltage, in order to simplify defect consideration in the event of a possible short-circuit of one (or more) diodes. It is also advantageous only to use diodes from the same manufacturer in order further to reduce irregular defect probability.
- a current i is measured across the resistor 8 in FIG. 1 . If the circuit for the ideal behavior as shown in FIG. 2A is incorporated into the circuit as shown in FIG. 1 , that gives the behavior shown in FIG. 5A for i, with a maximum current of i 5 . That can be explained by the diode 21 , by which the negative half-wave is cut off in the reverse direction.
- circuit for the real behavior as shown in FIG. 2B is incorporated into the circuit shown in FIG. 1 , that gives the behavior shown in FIG. 5B , with a maximum current in the positive direction of i 1 and in the negative direction of i 2 . It also follows from the equivalent circuit shown in FIG. 2B however that i 1 is greater than i 5 (i 1 >i 5 ) as the resistor 22 is additionally connected in parallel. Now however a current can also flow through theat resistor 22 in the negative half-wave, which current has its maximum at i 2 but which in magnitude is smaller than i 1 .
- FIG. 4C shows a symmetrical voltage U 2 *, as is known from the state of the art and which is measured at the same measurement points C and D as the voltage U 2 . If, as already indicated above, the circuit for the real behavior as shown in FIG. 2B is incorporated into the circuit shown in FIG. 1 , that, with the symmetrical behavior of the voltage U 2 * which is known from the state of the art, gives the behavior shown in FIG. 5C with a maximum current in the positive direction of i 3 and in the negative direction of i 4 .
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
- Measurement Of Current Or Voltage (AREA)
- Control Of Combustion (AREA)
- Fire-Detection Mechanisms (AREA)
Abstract
Description
Claims (10)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10125574A DE10125574A1 (en) | 2001-05-25 | 2001-05-25 | Flame monitoring device with which an asymmetrical voltage is applied across burner and ionization electrode to detect presence of flame |
DE101255748 | 2001-05-25 | ||
PCT/IB2002/001758 WO2002095295A1 (en) | 2001-05-25 | 2002-05-22 | Flame-monitoring device |
Publications (2)
Publication Number | Publication Date |
---|---|
US20040178915A1 US20040178915A1 (en) | 2004-09-16 |
US7046154B2 true US7046154B2 (en) | 2006-05-16 |
Family
ID=7686155
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/477,005 Expired - Lifetime US7046154B2 (en) | 2001-05-25 | 2002-05-22 | Flame-monitoring device |
Country Status (5)
Country | Link |
---|---|
US (1) | US7046154B2 (en) |
EP (1) | EP1390668B1 (en) |
AT (1) | ATE366395T1 (en) |
DE (2) | DE10125574A1 (en) |
WO (1) | WO2002095295A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005024763B3 (en) * | 2005-05-31 | 2006-06-08 | Stiebel Eltron Gmbh & Co. Kg | Heating device, has combustion chamber with ionization electrode for detecting ionization signals and evaluation unit coupled with fuel valve for controlling of fuel valve in dependence of evaluated time process of alternating voltage |
EP2154430B1 (en) * | 2008-08-15 | 2015-09-30 | Siemens Aktiengesellschaft | Control device for a gas burner, and use of the control device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1230165B (en) | 1964-08-07 | 1966-12-08 | Danfoss As | AC-powered flame guard |
US3378733A (en) | 1964-05-22 | 1968-04-16 | Danfoss As | Supervisory switching arrangement |
DE1815968A1 (en) | 1967-12-26 | 1969-08-07 | Combustion Eng | Method and device for flame monitoring |
JPS59217417A (en) | 1983-05-25 | 1984-12-07 | Matsushita Electric Ind Co Ltd | Kerosene room heater |
US5899683A (en) | 1996-05-09 | 1999-05-04 | Stiebel Eltron Gmbh & Co. Kg | Process and device for operating a gas burner |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4122636C2 (en) * | 1991-07-09 | 1999-08-12 | Bosch Gmbh Robert | Device and method for monitoring a flame |
DE19605803A1 (en) * | 1996-02-16 | 1997-08-21 | Daug Deutsche Automobilgesells | Circuit arrangement for ion current measurement |
DE19712373A1 (en) * | 1997-03-25 | 1998-10-01 | Bosch Gmbh Robert | Device for monitoring a burner |
DE19712938C1 (en) * | 1997-03-27 | 1998-05-14 | Honeywell Bv | Burner flame monitor supply voltage circuit for power plant |
-
2001
- 2001-05-25 DE DE10125574A patent/DE10125574A1/en not_active Withdrawn
-
2002
- 2002-05-22 WO PCT/IB2002/001758 patent/WO2002095295A1/en active IP Right Grant
- 2002-05-22 AT AT02727938T patent/ATE366395T1/en not_active IP Right Cessation
- 2002-05-22 US US10/477,005 patent/US7046154B2/en not_active Expired - Lifetime
- 2002-05-22 DE DE50210419T patent/DE50210419D1/en not_active Expired - Lifetime
- 2002-05-22 EP EP02727938A patent/EP1390668B1/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3378733A (en) | 1964-05-22 | 1968-04-16 | Danfoss As | Supervisory switching arrangement |
DE1230165B (en) | 1964-08-07 | 1966-12-08 | Danfoss As | AC-powered flame guard |
DE1815968A1 (en) | 1967-12-26 | 1969-08-07 | Combustion Eng | Method and device for flame monitoring |
JPS59217417A (en) | 1983-05-25 | 1984-12-07 | Matsushita Electric Ind Co Ltd | Kerosene room heater |
US5899683A (en) | 1996-05-09 | 1999-05-04 | Stiebel Eltron Gmbh & Co. Kg | Process and device for operating a gas burner |
Also Published As
Publication number | Publication date |
---|---|
EP1390668A1 (en) | 2004-02-25 |
DE10125574A1 (en) | 2002-11-28 |
DE50210419D1 (en) | 2007-08-16 |
EP1390668B1 (en) | 2007-07-04 |
WO2002095295A1 (en) | 2002-11-28 |
US20040178915A1 (en) | 2004-09-16 |
ATE366395T1 (en) | 2007-07-15 |
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Owner name: SIEMENS BUILDING TECHNOLOGIES AG, SWITZERLAND Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BOTT, KLAUS;DIEBOLD, ALEXANDER;HOFFMANN, JURGEN;AND OTHERS;REEL/FRAME:016046/0010;SIGNING DATES FROM 20031012 TO 20031022 |
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AS | Assignment |
Owner name: SIEMENS SCHWEIZ AG, SWITZERLAND Free format text: MERGER;ASSIGNOR:SIEMENS BUILDING TECHNOLOGIES AG;REEL/FRAME:030655/0436 Effective date: 20040928 |
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